346 J. D. IVES 



period than those areas below the trim hue, and that this period embraced 

 the maximum of at least the Classical Wisconsin glacial equivalent. 



For 100 to 125 m below the trim line, both Loken and Ives have described 

 the occurrence of incipient mountain-top detritus (Ives. 1958b; Loken, 1962a). 

 Andrews, furthermore, has described the same phenomenon in the Kiglapait- 

 Nain area farther south (Andrews and Matthew, 1961). This may be equated 

 with DahTs incipient detritus in Norway (Dahl, 1961) and it is again argued 

 that the time factor is vital to an understanding of its development. Its lower 

 limit is marked by a striking series of lateral moraines and kame terraces, 

 below which evidence of recent glacial activity is everywhere abundant. The 

 present author originally interpreted the upper trim line as marking the maxi- 

 mum vertical extent of the last or Koroksoak Glaciation, and the lateral 

 moraine system as representative of a recessional phase of the Last Glaciation 

 (Ives, 1958a, 1960). Andrews followed Dahl by suggesting that the incipient 

 detritus developed, in part at least, during the last glaciation and that the 

 lateral moraine system marks the upper limit of that glaciation to which he 

 gave the name "Sagiek" (Andrews. 1961; Dahl. 1961). In this scheme the 

 Koroksoak becomes the penultimate glaciation. and the Torngat Glaciation, 

 during which the high level erratics are believed to have been emplaced. older 

 still. ^ 



The Saglek lateral moraine system has been traced both in the field and on 

 air photographs over a north south distance of more than 400 km (Ives, 1960; 

 Loken, 1962a; Tomlinson. pers. comm. 1961 ; Andrews and Matthew. 1961). 

 Below them extensive end moraine systems occur and Loken has related 

 individual end moraines to Late-Glacial sea level phases. He has also obtained 

 a radiocarbon date of 9000 years B.P.* for a condition when some of the north- 

 ern fjords already contained no tide-water glaciers, while farther south outlet 

 glaciers still reached the Atlantic Ocean (Loken, 1962b). Andrews has studied 

 several massive end moraine systems in the Kiglapait-Nain area which 

 appear to overlie extensive deposits of varved clays up to 20 m thick. The 

 implication is that subsequent to the Saglek lateral moraine phase, several 

 major halt and readvance phases occurred. This evidence supports the 

 contention that the Saglek moraines are appreciably older than 9000 years 

 and may indeed represent the equivalent of the Classical Wisconsin maximum. 



From the foregoing discussion it will be seen that an attempt is being made 

 to tackle the problem of the relative age of the mature mountain-top detritus 

 indirectly — namely, by considering the relative and absolute ages of the 

 extensive lateral and end moraine systems, thereby obtaining a minimum 

 age for the mature detritus. One further step in this reasoning process is 



* Personal communication from Dr. W. S. Broecker, 1961. Marine molkiscs were 

 collected at 29 m above sea level by Dr. O. Loken and submitted to Dr. Broecker by the 

 Geographical Branch. The Lamont Geological Observatory laboratory number of the 

 sample is L-642. 



